1. Field of the Invention
The preset invention relates to a method for driving an active matrix type display device that uses, for example, an organic electroluminescent element (hereinafter referred to as an organic electroluminescent element), and in particular, to a method for driving an active matrix type display device which prevents horizontal emission lines or the like from occurring on a screen upon power-on or upon application of a full screen signal, to maintain image quality when driving is started.
2. Description of the Related Art
Active matrix type display devices using organic electroluminescent display elements have been developed. These devices require that the characteristics of driving transistors that drive organic electroluminescent display elements are almost the same among pixels. However, the transistors are normally formed on an insulator such as a glass substrate. The transistor characteristics are thus likely to vary.
To solve this problem, a threshold cancel type circuit and a current copy type circuit have been proposed (see U.S. Pat. Nos. 6,229,506B1 and 6,373,454B1). These circuits can eliminate the adverse effect of a threshold for the driving transistor on a driving current. Consequently, in spite of a variation in the threshold for the driving transistor among the pixels, it is possible to minimize the adverse effect of the variation on the driving current supplied to the organic electroluminescent elements.
The above effect of the threshold cancel type circuit or current copy type circuit is exerted while the display device is operative. However, the present inventor notes the image quality obtained upon power-on or when such a signal as turns the entire screen, for example, black is applied. A sequence for application of power supply voltages to the appropriate sections of the display device is preferably such that after the power supply voltages for a drive circuit and a pixel circuit are stabilized, scan signals and pixel select pulses for the pixel circuits are sequentially output. However, even such activation has been found not to be preferable for image quality; this operation may involve the occurrence of partial horizontal emission lines or the like.